Grand Seiko 6156-8010 “Special”
From 1970, the 6155 (date) and 6156 (day-date) “Specials” were regulated to +/- 3 seconds per day, whereas the “Grand Seiko standard” was -3/+5 seconds per day. Only the VFA’s were more accurate at timekeeping than the Specials.
It’s interesting to note that even today, the Grand Seiko standard remains at that same -3/+5. There have only been a handful of modern mechanical Grand Seikos regulated as accurately as these vintage pieces. In fact, I believe that in total Grand Seiko have made (or have committed to make) just 1036 watches with similar accuracy. Those are the SBGH019/020/022 – respectively in white, yellow and rose gold, each limited to 200 pieces; the SBGH035 in steel, limited to 300 pieces; and the recently announced tribute to the first Grand Seiko, the platinum cased SBGW251, limited to 136 pieces. These modern pieces are regulated to -1/+5 seconds per day.
So as you will hopefully now appreciate, these vintage “Specials” truly are deserving of their name.